Yes, but don't just take their word for it. Confirmed clinical test should be the bar. I fear if the "you don't need a vaccine if you've had it" narrative gains traction, even if it is undeniably true, it's going to result in the anti-vaxxers lying about having already had the virus, to manufacture another excuse for themselves. If we've learned anything in the last year, it's that any system that relies on people to pinky-swear they're telling the truth will be exploited by a small but significant minority of people.